1. Field of the Invention
The invention relates to a rotor assembly such as a propeller having a blade.
2. Description of Related Prior Art
U.S. Pat. No. 2,670,050 discloses a multi-blade propeller and cowling therefor. In brief, the invention of the '050 patent includes a small propeller hub having slender integral rigid spokes radiating therefrom, the spokes at their outer ends carrying sockets within which propeller blades are rotatably mounted for pitch change. The hub sockets, spaced circumferentially from one another, are joined by structural ties. The radially outward spacing of the hub sockets enables the use of a large multiplicity of blades which would not be possible, due to interference of the sockets with one another, if the sockets were disposed close to the axis of rotation. The spokes preferably may be solid structural members of minimum diameter, thereby offering minimum drag to air which may flow through the propeller hub inwardly of the blade sockets. A pitch change mechanism is incorporated in the central portion of the propeller hub and drive shafts lead therefrom to each blade in each socket, preferably, parallel to the hub spokes, to impart pitch changing rotation from the central hub to the remotely mounted blades. This propeller hub is particularly adapted for use with a so-called NACA type E cowling wherein a spinner, with an axial air entrance opening, is mounted upon the propeller and cooperates with a fixed cowling. Airflow through the spinner passes to a turbine engine or the like, across the spokes of the propeller hub, while the multiplicity of blades, exteriorly of the spinner, operate upon the air for propulsion of the aircraft. The multiple blade propeller made possible by this invention is particularly adapted for transonic flight speeds, but is not limited to such speeds. Fairings are referenced at 40 in FIGS. 2-4. The fairings are fixed to radially inner and outer portions of a spinner. Column 3,lines 15-21. The fairings can be pitched to an appropriate angle according to the direction of airflow through the spinner. Column 4, lines 45-50.